A space agency compares three locations relative to the Earth’s surface:
• Station P: altitude 400km (h=4.00×105m),
• Station Q: an underground laboratory at an unknown depth d,
• Station R: a weather balloon rising to an altitude hR.
Take RE=6.4×106m and g=9.8ms−2 at the surface.
a. (i) Calculate gP, the gravitational acceleration at Station P.
b. (ii) If gQ equals gP, compute the required depth d for Station Q.
c. (iii) Station R is to be located so that gR is exactly midway between the surface value and gP. Determine the altitude hR that satisfies this condition.
d. (iv) Between Stations Q and R, indicate which one is closer (in linear distance) to the Earth’s surface and support your answer with numerical values.